1. Field of the Invention
This invention relates to methods for plating printing rollers and more particularly to plating of photogravure plates and to mounting apparatuses for such rollers utilized in the plating method.
2. Prior Art
In order to provide homogeneous plating of a gravure roller, at least a part of the roller surface must be immersed in a process solution and the roller must be rotated with precision at a specified constant rate. In addition, in order to carry out the plating in a short time period, it is desireable to immerse the whole body of the roller in the process solution. Consequently, because the gravure roller is hollow in shape, some action must be taken to prevent the process solution from leaking to the inside of the roller.
With such a necessity, in conventional plating processes for gravure plate making, action is taken as follows: a spindle is inserted through the hollow gravure roller; both ends of the roller are supported with a pair of ring shaped charge-supporters provided on the spindle; ring shaped leakproof caps are provided on the spindle to cover both of the charger-supporters and seal the ends of the roller; and the completed set-up is then mounted on a pretreatment apparatus, then mounted on plating apparatus, and then mounted on a after-treatment apparatus. However, in such a procedure, manual mounting is indispensable, and complete automatization has been hindered. Also, in such a process a great amount of man power is required and work efficiency is low.
In addition, in another conventional example, the Europena gravure plate maker is equipped with an apparatus to automatically mount the gravure roller onto the pretreatment apparatus, plating apparatus, and after-treatment apparatus or to dismount the roller from each of them respectively as well as to rotate the roller. However, such a structure has certain disadvantages as is described below. Firstly, the cost is high because an automatic mounting apparatus is required for each pretreatment, plating and after-treatment apparatus. In addition, the mounting must be done on each apparatus and therefore the time required for the process increases. In addition, since there are required a great number of mountings and dismountings of the roller, the chance of a leak into the inside of the roller is increased. Furthermore, because the roller is directly lifted onto and off of each one of the apparatuses, there is a substantial possibility that the roller surface will be scratched and to avoid such scratching the rollers must be handled carefully and with a soft material such as a cloth.